Water heater



Feb. 21, 1933. D B. W|LL|AMSON 1,898,703

WATIERU'. HEATER File/July 5,0, 1932 2 sheets-sheetA 1 INVENTOR Feb. 21,1933. D, B. wlLLllAMsoN WATER HEATER Filed July 30, 1932 2 Sheets-Sheet2 5 lNvENToR MMM Patented Feb. 2l, 1933 PATENT cartes noNatnmwnLIamtsQN.or HTTSBURGH, rnNasYLVemae-sssmm .T0 -raEfPeQI-@S .NATrnALnas GQMBANLA.solares-mortier.PENNSYLYAMA WATER HEATER .natation med July.

n, This invention relates to a water heater of the side arm type. Thatis to a water heater comprising both a storage tank `and a; heaterproper, which latter is in return communication withthe storage tank.

The specific type lofwate'r heater to which the improvements of myinvention are applied has a cold water inlet to the tank in the yupperregion thereof; a Warm water outlet .Y

from the lower region of the tank4 to the heater coil; and a Vreturnline-from the -ldischarge `end of the heater coil .to :the tank, thisreturn line extendreverse flow to the-discharge end ofthe heat- 25 oitsuch type a control thermostat for the gas'V ing coil, is prevented.Previously in a heater -lineto the heating coil has beenpositioned ,A an

Vwithinthel tank, and inthe lower region thereof. Y

Thistype .of heater, as deinitely described aboveisv prompt in itsaction, andis reasonablyetticient. l. It carries, however, an unduly.hightank temperature; and the hottest region ofthe tank` being theupper regionltherein, :there is a substantiallossof heat by radiation. Adefect in operation is that a.con.Y siderable quantity :of` cold .watermust enter i (the tank beforethe thermostat operates to tothe lowerregion temperature, operates to cut off gas supplyto the burner.

The primary object offthis vinvention .is to improve a waterheaterofthedescribedtype y by so positioning and associating-.the control Y 5;.Service withdrawal Of Weten and .that 'ifats vthermostat thatu itacts/instantaneously to supplyfgas totheburner of the 4heliating coilupon :the top of l,the tank. A

pipe 3 leads from the .bottom .of the tank ,to a heater proper 4, whichlis to, be.understood as i932. `serial v No. vezegieo.

under the inuence of thehighest .tank 4tem- Y .peraturelto cutloffgassupply at timeswhen no' withdrawalis'being made.

.A .furtherfobject of the invention is to` provide means guardingagainst objectionably .high temperature ofservicewater in1large`capacity installations.

4In the accompanying drawings-Figure. I is an .elevational view,Ashowing a heater` embodying` the primary improvements 'of `my in-.vention Figure II is a fragmentary elevational view, showing ainodifled positioning of. the control,thermostaty-Figure; III is aVfragmentary elevational v4view .showing the use of athermostat forcontrolling'the temperature .ofy waterfflowiiig kto service, and

adaptable foraddition toeither structure ilulustrated in Figures IandII, andFigure `IV is a detail view, in vertical section, showingthecheck valvel comprised in the apparatus andthelitting in which itisinstalled. y

In. the. drawingsreference numeral l desf-ignates the storageitankof theheater, which has acold watersupply pipe@ l,coniiecjtefdf at comprisinga heating coil ,.or its equivalent heating element, to the intake endofgwhich pipel l3 connects. pThe heater. proper also comprises a burnerof knownsort, a lportion v ofwhichis shown at 5. @The heaterfllhastheoutletof itsheatingelement connectdto a discharge pipe 6.

l Disjchargapipe dbranches; onehbranch 7 vextending downwardly ,in tanky1;v to a point adjacent the bottom4v thereof andf theothen or service,.branch` 8l v leading to a Vfaucet or vvsupply gas tothe .burner of theheating coil. Conversely, the temperature in the .upper re- Y .Y gion ofthe tank reaches the highteinperature noted, before the thermostat,`being regulated bottom ofthe tank byfvv'a'yfotpipe, Gwand 100 warm Wateroutlet branch 7 At times of service withdrawal circulation is from thebottom of tank 1, through the heater 4, and from the heater, by way ofpipe 6 and service branch 7 to service.A All service water is takendirectly from the heater.

The gas supply line 10 has therein a pilot burner 11, and thereafterenters heater burner 5 to supply fuel thereto. The automatic gas controlmeans act to control gas flow in the region between pilot burner 11 an-dthe main burner 5.

Fuel supply to burner 5 is controlled by a suitable valve 12, operatedby thermostat 13. As shown in Figure I of the drawings, thermostat 18 ismounted in a fitting 14 of cold water supply pipe 2, and comprises abulb extending downwardly into the tank from the top thereof.

It is to be understood that communication.

1 enters the tank in its lower region and moves upwardly throughoverlying water to the upper region ofthe tank. rThis current tends toproduce an equalization in the temperature of tank water, but inevitablyduring `the continuance of these conditions the upper region of the tankbecomes the most `highly heated region. The cycle continues until thewater temperature in the upper region of the tank becomes elevated tothe point at which thermostat 13 has-beenV set to operate in cutting 0Hfuel supply to the burner.

v 45 By exposing the control thermostat to the highest normal tanktemperature, the tank temperature is definitely limited for all regionsthereof. When a mostat setting has been produced in the upper region ofthe tank, the thermostat operates to again supply fuel to the heaterburner.

Hot water then passing from the heater to the tank does not affect thethermostat until it has risen from a point adjacent the bottom ofthetank to the upper portion thereof in the region of the thermostat.

A service withdrawal of water from the.

:system instantly causes cold water to enter Y at the top of the tankfrom supply pipe 2.

This cold water, acting Aon thermostat 13, operates gas valve 12 tosuply fuel to burner 5. Substantially all thewater passing to service;from the bottom of tank 1,. and through heater 4, is directly-heatedduring 6s its passage through the heater. l A very slightA initialwithdrawal of Water suiices to chilling below ther-l supply fuel to theheater burner, and thereby causes all succeeding water to be highlyheated in passing to service.

As thus subjected to inflowing cold water, the thermostat is caused toact much more promptly thanif subjectedonly to tank temperature, and thepromptness of thermostat action is even more marked in comparison with asystem in which the-thermostat acts under the temperature influence ofwater in a lower region of the tank.

In the modification shown in Figure II ofthe drawings, the thermostathas a highly specialized mounting in the extreme upper region of tank@temperature influence. In this modication cold water supply pipe 2 isprovided with a horizontal extension 15 in which the bulb ofathe'rmostat13 lies. A tting 16 gives access to the interior of tank 1 at the upperextremity thereof.

In normal operation of the system, that is when no withdrawalis made,water atrthe highest permitted tank temperature rises through fitting16, and surrounds the bulb .the water in the tank causes hot watertoagain enter extension 15 in such manner that the thermostat is subjectedwholly to its influence.

Advantages of myY improved water heater are the instantaneous deliveryofhot water at'thc faucet, and the continued delivery of a relativelygreat volume of water` without appreciable drop in. faucet temperature.

. There is furtherthe advantage, based on the manner in which thecontrol thermostat is influenced, ofmaintaining a lower average tanktemperature at all times, and economizing in fuel consumption bylessening radiation loss in theupper region of the tank. My waterheater, to the fullest extent yet realized, combines the advantages ofan instantaneous water heater with the advantages of a tank typewaterheater.

As a specific example, my water heater, when constructed'with a 15gallon tank and a 25,000 B. t. u. coil, delivers water atatemperatureabove 110 Fahrenheit fortan indeiinitetime. Extremely low rates-of flowproduce rather high, but not. dangerous,fau cet temperatures, and the'faucet .temperature may be easily reduced by increasing the volume oflflow. lThe feature kof faucet temperaturecontrol is governed by heatingcoil capacity, tank rtemperature (thermostatic control at the tank), andas a controllable element, the rate of flow. l

I have found that my water heater in very large installations is notadequately under faucet control in determining the upper limit of faucettemperature. In installations, therefore, which approximate or exceed atank capacity 6() gallons and a 45,000 B. t. u. coil I prefer to addautomatic means for limiting positively faucet temperature.

Figure III of the drawings illustrates the use of an independentthermostat to definitely limit the temperature of the water in theservice branch pipe 8. In such modification the loop of gas line 10lying between pilot burner 11 and main burner 5 is greatly extended, asfor a yard or more, along service branch 8. This extended portion of gasline 10 has therein a valve 17, which is under the control of athermostat 18 in the pipe 8.

This thermostat 18 controls only vthe temperature of service water tothe faucet to cut off the gas supply to the burner when a predeterminedtempera-ture for service water has been exceeded. Y

The two thermostats 13 and 18 do not act in a differential manner, anddo not either of them interfere with the action of the other; one actingto control tank temperature, and the other acting to control servicewater temperature which is materially higher than tank temperature. Whenits action in cutting off gas supply has lowered the temperature of thewater in pipe 8 to the point of safety, thermostat 18 gradually opensvalve 17, and restores complete control of the system to thermostat 13.As explained thermostat 13 closes its associated valve 12 only at suchtime ascessationof water withdrawal has permitted tank temperature to beagain built up to the normal carrying point.

I claim as my invention:

1. In a water heater having a circulation system comprising a storagetank, a heating element, a cold water line entering vat the upper end ofthe storage. tank, an outflow line at the lower end ofthe storage tankleading to the inlet end of the heating ele-ment, a branched dischargepipe from the outlet end of the heating element having one branchthereof leading to service and another branch thereof dischargingintermediate the height of the tank and having therein means preventingsubstantial return flow through that branch to the heating element or toservice; the combination of a burner for the heating element, a gassupply line tosaid burner, and a control thermostat subjected by itsposition of mounting to the direct chillingl effect of the cold waterline to the tank upon and during service withdrawals of water from thecirculating system and subjected to the effect of tank water temperaturein the extreme upper region of the tank in periods between serviceWithdrawals of water.

2. The combination of the next preceding claim in which the thermostatis mounted in an extension of the cold water supply line in a positionwholly outside the storage tank, and in which by a connection from theextreme upper region of the tank to the extension of the cold watersupply line in which the thermostat is mounted the thermostat issubjected to tank water temperature in the extreme upper region of thetank during periods between service withdrawals of water.

3. In a water heater having a circulation system comprising a storagetank, a heating element, a cold water line entering at the upper end ofthe storage tank, an outflow line at the lower end of the storage tankleading to the inlet end of the heating element, a branched dischargepipe from the outlet end of the heating element having one branchthereoflleading to service and another branch thereof dischargingintermediate the height of the tank and having therein means preventingsubstantial return flow through that branch to the heating ele-ment orto service; the combination of a burner for the heating element, a Vgassupply line to said burner, a main control thermostat subjected by itsposition of mounting to the direct chilling effect of the cold watersupply line to the tank upon service withdrawals of water from thecirculating system and subjected to the effect of tank water temperaturein the eXtreme upper region of the tank in periods between servicewithdrawals of water, and a thermostat disposed in the service branchpipe from the heating element to service and acting independently of themain control thermostat during service withdrawals of water to impose anupper limit of temperature 0n Water passing from the heating element toservice.

4. The combination of the next preceding claim in which the main controlthermostat is mounted in an extension of the cold water supply line in aposition wholly outside the storage. tank, and inv which by a connectionfrom the extreme upper region of the tank to the extension of the coldwater supply line in which the main control thermostat is mounted thethermostat is subjected to tank water temperature in the extreme upperregion of the tank during periodsl between service withdrawals of water.

In testimony whereof I have hereunto set my hand.

DONALD B. WILLIAMSON.

